Torque converters are well known in the art. Torque converters which include torque converter lock-up clutches, which mechanically couple the input to the output of the torque converter, are also known. In some torque converters, the lock up clutch is engaged by pressing a piston away from the pump and turbine, and directly against a cover of the torque converter.
In other torque converters, such as the one shown in FIG. 1, the lock up clutch is engaged by pressing the piston in a direction towards the pump and turbine of the torque converter. In such a scenario, a backing plate is required to provide the clutch with a support means to engage against. Torque converters which include such backing plates are also disclosed in U.S. Pat. No. 2,821,867 (Kelbel), U.S. Pat. No. 2,971,385 (Miller), U.S. Pat. No. 2,691,812 (Misch), and U.S. Pat. No. 2,640,373 (Jandasek). These prior art backing plates must be quite thick so that they have sufficient stiffness to ensure that they do not bend and can accordingly provide a support means for the engagement of a clutch.
Due to the large thickness, the backing plates can only be manufactured from certain manufacturing techniques, most commonly fine-blanking. Fine-blanking, however, is quite expensive due to the specialized equipment and tooling required to perform the blanking operation. U.S. Pat. No. 7,063,197 (Merkel et al.) discloses a backing plate having a smaller thickness than traditional backing plates so that fine-blanking is not necessary, but the plates in Merkel et al. require substantial and accurate bending and shaping. Further, the area on the Merkel et al. backing plate that is engagable against the clutch is substantially reduced in comparison to traditional backing plates.
Therefore, what is needed is a backing plate which does not require specialized fine-blanking equipment to manufacture, but which has sufficient stiffness and surface area to provide a support means for the engagement of a clutch.